By Josie Powel

The researchers analysed anonymised data that tracked 100 million installations of apps adopted by Facebook users over two months in 2007. The data allowed researchers to observe on an hourly basis the rate at which 2,700 apps were installed by 50 million Facebook users. They discovered that once an app had reached a rate of about 55 installations a day, its popularity then soared to reach stellar proportions. A typical app was installed by 1,000 users, but the most popular app ‘Top Friends’ was in a different league, being adopted by almost a fifth (12 million users) of the entire Facebook population.

The study concludes that social influence had a key role in whether apps became flops or hits. Crucially, when the data was monitored in 2007, Facebook friends would always be notified if one of their online friends adopted a new app. All Facebook users could also see a list of the most popular apps – similar to best-seller lists – so knew how the ‘global’ as well as their ‘local’ community of Facebook friends rated the apps.

Senior researcher Dr Felix Reed-Tsochas, from Oxford University’s Institute for Science, Innovation and Society at Saïd Business School, said: ‘Our analysis reveals a very interesting new finding. Users only appear to be influenced by the choices of other users above a certain level of popularity, and at that point popularity drives future popularity. Below this threshold, the effects of social influence are imperceptible. Because popularity seems to depend mainly on the choices of other users in the community, rather than intrinsic characteristics of the applications themselves, it does not appear possible to predict which applications will succeed and which will fail ahead of time.’

The study points out that its observations have implications for the online world. Online book retailer Amazon and the online DVD rental service Netflix already allow their users to rate the products and, as a consequence, influence their future popularity. The study concludes that while some books and films are highly advertised by their producers, that element is only a small fraction, leaving the large majority of books and films exposed to the forces of social influence. It argues that social influence may emerge spontaneously in a wide range of online environments and asks whether these findings could tell us something about the way we behave in the offline world too.

Dr. Reed-Tsochas commented: ‘There has been a lot of research into the spread of ideas and products. Previously, we have only been able to track the spread of successful innovations, and then only among a small set of potential users. Our research in the virtual world of online social networks is the equivalent to moving from a fixed telescope that lets us view a restricted number of stars to having a complete map of all the stars in the universe.

‘At this stage, we simply don’t know whether this marks an important difference between offline and online behaviour, or whether more detailed and comprehensive data from offline contexts will identify similar collective behaviour in settings that do not involve online environments.’

About the author

Josie Powell is Public Relations Coordinator at University of Oxford. Direct telephone: +44 (0) 1865 422573/288403. Emails: josie.powell@sbs.ox.ac.uk, or pressoffice@sbs.ox.ac.uk.

About the research

‘The spontaneous emergence of social influence in online systems’ co-authored by Felix Reed-Tsochas and Jukka-Pekka Onnela was published by PNAS (Proceedings of the National Academy of Sciences) on Monday 11 October. The data used by the research team contains no information about individuals, and only information about individual applications, so there are no implications in terms of the privacy of individual Facebook users.

The research was funded by the European Commission via the ICTeCollective project. For more information, see http://www.becs.tkk.fi/ictecollective/.

The top 10 Facebook applications at the time that data was collected (25 June-14 August 2007): 1.Top Friends (1,1962,481 users); 2.Video (6,487,572 users);3.Graffiti (6,335,873);4.My Questions (6,324,224); 5.iLike (5,988,584); 6.Free Gifts (5,282,413); 7.X Me (5,236,443); 8.Superpoke! (5,175,439); 9.Fortune Cookie (4,774,815); 10.Horoscopes (4,555,010).

About Felix Reed-Tsochas

Felix Reed-Tsochas is a James Martin Lecturer in Complex Systems and Co-Director of the CABDyN Complexity Centre. The Oxford Martin School was founded as the James Martin 21st Century School at the University of Oxford in 2005 through the vision and generosity of Dr James Martin. It is a unique interdisciplinary research initiative tackling global future challenges. See http://www.oxfordmartin.ox.ac.uk.

Dr Reed-Tsochas is available on 07789 146737or email: felix.reed-tsochas@sbs.ox.ac.uk.